The deployment of cellular networks, satellite networks and other wireless networks has greatly expanded the use of mobile wireless communication devices. Whether a wireless communication device is a handheld device or a vehicle mounted device, there is an interest in making the devices small so that they can be conveniently carried or accommodated in small spaces.
Advances, by many orders of magnitude, in the degree of integration and miniaturization of electronics over the past few decades have facilitated extreme miniaturization of transceiver electronic circuits. However, the methods and means used to miniaturize electronic circuits cannot always be applied to miniaturize antennas because antennas operate under the principles of Maxwell's equations, which, roughly speaking, stipulate that if antenna efficiency is to be preserved, the size of the antenna must be scaled according to the wavelength of the carrier frequency of the wireless signals that are to be received and/or transmitted.
Compounding the challenge of reducing antennas size is that for many wireless communication devices, the antenna system needs to support operation at multiple frequencies, for instance, in multiple relatively wide frequency bands. However, using separate antennas to support separate operating frequencies has also led to difficulty in reducing the space occupied by the antenna system.
In addition, other antenna systems have attempted to transmit circularly polarized radiation. Unfortunately, these systems have not been able to be successfully miniaturized, for at least the reason that individual antenna element bandwidth and efficiency are reduced upon miniaturization and, furthermore, elements forming a system have not been able to be properly isolated, thereby degrading system performance.
Thus, there exists a need for low profile antenna systems, which address at least some of the shortcomings of past and present techniques.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments. In addition, the description and drawings do not necessarily require the order illustrated. Apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the various embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Thus, it will be appreciated that for simplicity and clarity of illustration, common and well-understood elements that are useful or necessary in a commercially feasible embodiment may not be depicted in order to facilitate a less obstructed view of these various embodiments.